Its not impossible. Its called a body recomp. I had this happen to me while I was a newbie and didnt know anything about diet. Simply bought a protein shake and workout while diet remained the same albeit the little bit of effort to add in meat and eggs for my daily meals. Lost 8kgs and looking visibly bigger. Bought my first L sized tshirt hehe.

And tbh I really really hate cardio in the gym. Friggin boring. I play sports for cardio.